Sen. Dianne Feinstein jumped into the fray Friday over the Obama administration's immediate response to the attack on the U.S. mission in Benghazi, Libya, defending U.N. Ambassador Susan Rice from "pillory" at the hands of Republicans.

The California Democrat and chair of the Intelligence Committee said, "We have seen wrong intelligence before, and it all surrounded our going into Iraq, and a lot of people were killed based on bad intelligence. And I don't think that's fair game. I think mistakes get made - you don't pillory the person."

Rice has been under heavy attack from Republicans led by Sen. John McCain, R-Ariz., and Lindsey Graham, R-S.C., who claim she misled the public in comments to Sunday news talk shows in September about the terrorist attacks on Sept. 11 that killed U.S. Ambassador J. Christopher Stephens and three other Americans. Rice initially attributed the attack to mob violence.

Petraeus told Feinstein's committee and the House Intelligence Committee that classified intelligence showed that terrorists conducted the attack but the administration kept the information secret to avoid tipping off the suspects, according to lawmakers at the briefings. Petraeus said it was not initially clear whether terrorists had infiltrated a demonstration to cover up the attack.

President Obama angrily defended Rice in a news conference earlier this week. Rice is considered a top contender to replace Secretary of State Hillary Rodham Clinton. McCain and Graham have made clear they would object to the nomination.

The issue flared up in the presidential race. Republican nominee Mitt Romney accused Obama in a debate of misrepresenting the attacks and deliberately downplaying the idea that terrorism was involved. Obama hotly denied it.

Feinstein said based on what she has learned, "What Susan Rice did was use talking points originally put out by the CIA, signed off by the intelligence community, and those talking points, as I understand it, were requested by the House Committee, and all the intelligence community signed off on them."

"The way it keeps going, it's almost as if the intent is to assassinate her character, and I really object to that," Feinstein said, adding that the talking points "subsequently became available to anybody I guess who asked for talking points, which the ambassador did."

McCain was also at the briefing but did not address the Rice controversy. He praised Petraeus for providing thorough testimony and conceded that there had been "clearly a failure of intelligence."

Senate Majority Leader Harry Reid, D-Nev., and House Speaker John Boehner, R-Ohio, both said no special committee is necessary. Several committees, including Feinstein's, are conducting investigations.

Republicans remained critical of security at the consulate. Sen. Marco Rubio, R-Fla., said Petraeus' testimony made clear that security was lax "despite an overwhelming and growing amount of information that showed the area in Benghazi was dangerous, particularly on the night of Sept. 11."

Feinstein said the original talking points given to Rice said: "The currently available information suggests that the demonstrations in Benghazi were spontaneously inspired by the protests at the United States Embassy in Cairo and evolved into a direct assault against the United States diplomatic post in Benghazi and subsequently its annex. There are indications that extremists participated in the violent demonstrations."

The talking points added: "This assessment may change as additional information is collected and analyzed and as currently available information continues to be evaluated."

"That's clearly what happened," Feinstein said Friday.

Feinstein is scheduled to appear on NBC's "Meet the Press," Sunday at 8 a.m.